Dr Ivy is a board certified pediatric cardiologist at the University of Colorado School of Medicine. He received his MD degree from Tulane University, and pediatrics and cardiology training from the Univ of CO SOM. As a Bugher Physician Scientist and Assistant Professor of Pediatrics, he has focused on clinical and basic science aspects of pulmonary hypertension in congenital heart disease and persistent pulmonary hypertension of the newborn. He has studied the role of endothelin (ET-1) in the normal fetal lung and in a model of pulmonary hypertension caused by in utero ligation of the ductus arteriosus. He has extensive experience in whole animal physiology, but only beginning training in molecular biology. RESEARCH: Pulmonary hypertension is a major cause of morbidity and mortality in children. ET-1 is a potent vasoconstrictor peptide which is increased in pulmonary hypertensive disorders; however, the role of ET-1 in pulmonary hypertension remains unclear. We will test the hypotheses that: 1) ET-1 acts in an autocrine fashion on vascular smooth muscle / ET-1 is produced on and stimulates smooth muscle proliferation 2) in chronic intrauterine pulmonary hypertension diminished nitric oxide production leads to elevated ET-1 production, 3) pressure stimulates production of ET-1 in the perinatal myocardium. The goals are: 1) to determine the cell specific expression of the ET system in the normal and hypertensive ovine fetal lung, 2) to determine if blockade of nitric oxide production leads to increased ET-1 production in the perinatal lung, 3) to determine the effect of changes in pressure on right and left ventricular expression of ET-1, ECE-1, and its receptors, and 4) to determine if blockade of endothelin converting enzyme activity attenuates chronic intrauterine pulmonary hypertension. ENVIRONMENT: Clinical and basic science studies of pulmonary hypertension are major focuses at the Univ of CO SOM. The laboratory environment at Univ of CO SOM comprises excellent clinicians / scientists with backgrounds in whole animal physiology and molecular techniques. Research presentations along with graduate level courses in molecular biology, and the clinical ambiance of the Univ of CO SOM in the area of pulmonary hypertension enhance career development.